[Progression to IDDM and islet cell antibodies (ICA; ICA-CF)].

We have followed eight first-degree relatives of IDDM patients (insulin-dependent, type I diabetes) attending the outpatient diabetes clinic at the State University of Rio de Janeiro for three years, all of them with positive islet cell antibodies (ICA and/or ICA-CF). Three out of eight relatives less than fifteen years old have subsequently progressed to overt Insulin-Dependent Diabetes Mellitus (IDDM) 12, 21 and 8 months after the first positive autoantibodies detection. Four relatives have remained with ICA and/or ICA-CF positive, and in another one the reaction became negative during the observation period. A positive correlation has been found between high titles of ICA (> or = 1/16) and development of IDDM. We have concluded from our prospective study during three years that of our antibody-positive relatives, 37.5 % have developed overt diabetes, all of them being less than fifteen years old, with high titles of ICA and ICA-CF positive.